The majority of failures in prosthetic implants and devices are caused by infections. Microbial infections are one of the major causes of these failures. The present article reviews various techniques such as modification in surface chemistry/composition and tailored structures (micro to nano) for improving the antibacterial response of prosthetic implants. In addition, the application of external stimulants such as magnetic and electric fields, as well as polarization, is recently realized as a fairly appealing approach to diminish the bacterial population. A comprehensive response of surface modifications as well as external stimuli in inducing the antibacterial response in prosthetic implants has also been summarized. The mechanisms for the antibacterial response due to these modifications, such as generation of toxic metal ions by dissolution of their respective oxides, and production of reactive oxygen species (ROS), such as singlet oxygen, hydroxyl radicals (OH–), hydrogen peroxide (H2O2), superoxides, peroxides (O2 –2), etc., have been elaborately discussed.

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Besides the excellent osteoconductivity and biocompatibility of 45S5 bioglass (BG), poor mechanical and electrical properties as well as susceptibility toward bacterial adhesion limit its widespread clinical applications. In this context, the present study investigates the effect of addition of piezo­electric sodium potassium niobate (Na0.5K0.5NbO3; NKN) on mechanical, dielectric, and antibacterial response of BG. BG–xNKN (x = 0, 10, 20, and 30 vol%) composites were synthesized at 800 °C for 30 min. The phase analyses using spectral techniques revealed the formation of the composite without any reaction between BG and piezo­electric ceramic NKN. The dielectric and electrical measurements were performed over a wide range of temperature (30–500 °C) and frequency (1 Hz–1 MHz) which suggests that space charge and dipolar polarizations are the dominant polarization mechanisms. The complex impedance analyses suggest that the average activation energies for grain and grain boundary resistances for BG–xNKN (x = 10, 20, and 30 vol%) composites are 0.59, 0.87, 0.94 and 0.76, 0.93, 1.06 eV, respectively. The issue of bacterial infection has been addressed by electrical polarization of the developed composite samples, at 20 kV for 30 min. Statistical analyses reveal that the viability of Gram-positive (S. aureus) and Gram-negative (E. coli) bacterial cells has been reduced significantly on positively and negatively charged BG–NKN composite samples, respectively. The qualitative analyses using the Kirby–Bauer test supports the above findings. Nitro blue tetrazolium and lipid peroxide assays were performed to understand the mechanism of such antibacterial response, which suggested that the combined effect of NKN addition and polarization significantly enhances the superoxide production, which kills the bacterial cells. Overall, incorporation of NKN in BG enhances the mechanical, electrical, and dielectric properties as well as improves the antibacterial response of polarized BG–xNKN composites.

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Coronavirus is a member of family Coronaviridae and subfamily Coronavirinae, which is large and enveloped RNA virus having the largest genomes (25-32 kb) among RNA viruses (Richman et al., 2016).The genome sequence of human coronavirus (HCoV) has four genera as Alphacoronavirus (α), Betacoronavirus (β), Gamacoronavirus (γ) and Deltacoronavirus (δ). Among all four HCoV, α and β coronaviruses are pathogenic (Woo et al., 2012). The domestic mammals (swine, mice, bat, etc.) and humans are suggested to be the origin and host for α and β coronaviruses, respectively (Lim et al., 2016). However, γ and δ coronaviruses are originated from birds and beluga whale, respectively (Geng et al., 2013). There are six β coronaviruses that infect the human respiratory system. Severe acute respiratory syndrome (SARS-CoV) and Middle East respiratory syndrome coronaviruses (MERS-CoV) are very infectious among the six existing HCoV [HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1 SARS-CoV, and MERS-CoV] (Li et al., 2005). The SARS-CoV was originated from bats and birds in China, in 2002, with the common cold as a general symptom (Kuiken et al., 2003). A report suggested that approximately 8000 patients were infected by SARC-CoV, worldwide (Gual et al., 2003). However, the mortality rate due to SARS-CoV infection was found to be ~10% (Wu, et al., 2020a). In 2014, in Saudi Arabia, new HCoV, MERS-CoV, similar to SARC-CoV was reported with a mortality rate of 35% (Morra et al., 2018;Terada et al., 2014).The MERS-CoV was originated from bats similar to SARS-CoV, later camels become an intermediate host (Bermingham et al., 2012;Crossley et al., 2003). In December 2019, a new respiratory viral infection has stated in Wuhan, China, which has been recognized by the family of HCoV. The HCoV family named this novel virus as SARC-COV-2, later World health organization (WHO) termed it as coronavirus disease-2019 (COVID-19).